# Siro funding: rounds and investors

> Siro has raised $50M across 1 round since 2025. Investors include SignalFire, Index Ventures and StepStone Group. Every round with its source.

Source: https://millionrounds.com/company/siro (Millionrounds; every figure on the page links to its filing or article)

[Series B startup](https://millionrounds.com/companies)

# Who invested in *Siro*

One round we have observed, with the 10 investors named in it. Every figure came from a named source, and where the company reported a raise to the SEC itself, that is shown beside it.

AI Salestech

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Funding summary Updated 5 Nov 2026

**$50M** raised across 1 round since 2025, from 3 sources

- **Latest round:** Series B, $50M May 2025
- **Led by:** SignalFire
- **Investors:** 10 (1 led)

See who backed them

## The rounds

- **May 2025** Series B **$50M** [SignalFire](https://millionrounds.com/fund/signalfire) Lead [Index Ventures](https://millionrounds.com/fund/index-ventures) [StepStone Group](https://millionrounds.com/fund/stepstone-group) [Fika Ventures](https://millionrounds.com/fund/fika-ventures) [01 Advisors](https://millionrounds.com/fund/01-advisors) [Michael Stoppelman](https://millionrounds.com/fund/michael-stoppelman) [Dave Salvant](https://millionrounds.com/fund/dave-salvant) [Ding Zhou](https://millionrounds.com/fund/ding-zhou) [Saumil Mehta](https://millionrounds.com/fund/saumil-mehta) [Songe LaRon](https://millionrounds.com/fund/songe-laron) Reported by TechCrunch and 2 others

## Everyone who backed them

[SignalFire](https://millionrounds.com/fund/signalfire) VC firm **1** round, led 1

[Index Ventures](https://millionrounds.com/fund/index-ventures) VC firm **1** round

[StepStone Group](https://millionrounds.com/fund/stepstone-group) Fund of funds **1** round

[Fika Ventures](https://millionrounds.com/fund/fika-ventures) VC firm **1** round

[01 Advisors](https://millionrounds.com/fund/01-advisors) VC firm **1** round

[Michael Stoppelman](https://millionrounds.com/fund/michael-stoppelman) VC firm **1** round

[Dave Salvant](https://millionrounds.com/fund/dave-salvant) Angel **1** round

[Ding Zhou](https://millionrounds.com/fund/ding-zhou) Angel **1** round

[Saumil Mehta](https://millionrounds.com/fund/saumil-mehta) Growth equity **1** round

[Songe LaRon](https://millionrounds.com/fund/songe-laron) Angel **1** round

Missing a round, or an investor who was in one? [Tell us](https://millionrounds.com/corrections?slug=siro).

## Also claim to have backed them

These 2 firms list Siro as a portfolio company on their own websites, but no report of a round names them. They are the firms' own claims, kept apart from the rounds above.

[CRV](https://millionrounds.com/fund/crv) VC firm Per its own site

[The MBA Fund](https://millionrounds.com/fund/the-mba-fund) VC firm Per its own site

## Quick answers about Siro

### Who invested in Siro?

Siro's investors include SignalFire, Index Ventures, StepStone Group, Fika Ventures and 01 Advisors, and 5 more on record. SignalFire led its latest round.

### How much has Siro raised?

Siro has raised $50M across 1 round since 2025.

### When did Siro last raise?

Siro's most recent round was a Series B of $50M in May 2025, led by SignalFire.

### What was Siro's biggest round?

Its most recent round, $50M in May 2025, is also its largest on record.

### Who backed Siro first?

Siro's first round on record, in May 2025, was backed by SignalFire, Index Ventures and StepStone Group and 7 others.

### What stage is Siro at?

Siro's latest named round is a Series B, in May 2025.

### Who led Siro's rounds?

SignalFire led the Series B in 2025.

## Companies like Siro

In the same sector, and raised in the last eighteen months.

[**Nirva** $25M · Oct 2026](https://millionrounds.com/company/nirva)[**Lovi** $15M · Oct 2026](https://millionrounds.com/company/lovi)[**Palma.ai** $1.8M · Sept 2026](https://millionrounds.com/company/palma-ai)[**Hang Ten Systems** $53M · Sept 2026](https://millionrounds.com/company/hang-ten-systems)[**OriginalVoices** $1.3M · Sept 2026](https://millionrounds.com/company/originalvoices)[**Positron AI** $875M · Sept 2026](https://millionrounds.com/company/positron-ai)

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